1. Field of Ivention
This invention relates to a continuous reciprocating linear motion piston and cylinder device, using pressurized fluid to operate.
2. Background of the Invention
Linear motion devices utilizing pressurized fluid, includes a movable piston, a pressure vessel comprising of a cylinder (piston guide) and a end surface to retain pressure also described as a “cylinder head” or “end cap”. The pressurized fluid fills the volume within the pressure vessel and one side of the piston causing the piston to move providing linear motion. The technology used for these devices are common knowledge in the hydraulic, pneumatic, and similar industries are usually generalized as a pneumatic or hydraulic “fluid cylinders” or simply “cylinders”. These fluid cylinders are classified as ‘single acting’ meaning pressurized fluid is applied to one side of the piston and returned by a mechanical force such as a spring and exhausts the spent pressurized fluid and ‘double acting’ meaning pressurized fluid is applied alternately to both sides of the piston and spent fluid is alternately exhausted. To provide continuous reciprocating movement when a pressurized fluid is applied, most common fluid cylinder devices must make use of a fluid valve not associated directly with the fluid cylinder device in order to pressurize and exhaust the fluid. A primary disadvantage of this type of mechanism is the addition of the valve itself. The addition of a valve provides an additional arrangement of moving parts also adding to the possible failure of the system. Secondly, the valve fluid flow position is not directly linked to the position of the piston stroke and becomes a disadvantage when the piston movement cycle does not complete due to rapid cycling, low pressure inlet, blocked exhaust or other limitation and may cause non-functionality or inefficiency of the mechanism. Additional devices, mechanisms, or sensors may be incorporated into the final machine to allow a method for timing between the valve and the position of the piston cycle but also increases the number of parts in the system. In addition, the valve and sensors or other means, must also be operated by mechanical and/or electrical means placing greater inefficiency of the final system.
There are many patents using fluid cylinders, valves, sensors and mechanisms as previously described and the method of manufacture is well known. References to companies manufacturing these fluid devices include, Bimba, Speedaire and Jenco.
Alternate designs of a linear piston and cylinder device incorporates a fluid flow ‘valve’ into the piston by using directional flow channels for fluid input and exhaust and where the fluid inlet pressure exhaust ports are located directly on the cylinder wall. When a flow channel on the movable piston aligns with the fluid ports on the cylinder wall, a reciprocating linear movement of the piston is the result. This type of fluid cylinder is generally used as a vibration device and has the benefit of being self contained, meaning; a valve and/or other external devices is not required for the basic function of the moveable piston. As long as adequate pressure is applied to the fluid input on the cylinder wall, the piston will automatically begin to cycle.
The primary disadvantage of this technology are the fixed fluid inlet and exhaust ports which limits the fluid energy applied to the piston due to only a brief alignment with the corresponding flow channels of the piston. Therefore, the piston movement must rely on momentum of the briefly pressurized fluid inlet, also known as the power stroke, while compressing the remaining trapped exhaust gasses ultimately causing inefficiency of the mechanism. The inability to control the piston position under variable loads limits the device to be ineffective when used in conjunction with as output shaft to drive an external device or mechanism.
A reference of a vibrator invention is disclosed in U.S. Pat. No. 6,044,709 (Briggs) whereas it is claimed that the invention provides a method for easier mounting and manufacturability than existing vibratory devices. There are also reference patents for this mechanism and use of the mechanism as disclosed by references made by Briggs, however, the functional fundamentals of the fluid device are essentially the same. Manufacturers of pneumatic vibrators include Cleveland Vibrator Co., Cleveland, Ohio, and Martin Engineering Co., Neponset, Ill.